Because of a higher carrier frequency, an optical signal has a wider carrier width and can carry more information than an electric signal. Therefore, optical communications technology is predominant in mass information transmission applications.
In a variety of equipment for optical communications, optical fiber is the most commonly used type of transmission and access device for transmitting optical signals and interconnecting different optical signal processing modules. Different from the conventional electric signal connection, which is shown in FIG. 1, in order to enable low-loss transmission of an optical signal from one optical fiber to another through their end faces joined together, coupling between the two optical fibers requires the end faces to be strictly parallel, in close contact, and aligned at the centers with each other.
As the optical signal has a very high frequency and accordingly very short wave length, an inner diameter of an optical fiber is much smaller than an inner diameter of a conventional electric wire. For example, a single-mode optical fiber is only 125 microns in diameter. Therefore, optical fibers themselves are not rigid, and in order to meet the above discussed requirements on end faces of the two optical fibers, i.e., being strictly parallel, in close contact, and aligned at the centers, an optical fiber clamp for fixing and positioning the optical fibers is generally used.
Currently, most of the commonly used optical fiber clamps are made of metal, plastic, ceramics, glass, or the like, and a method for fabricating such an optical fiber clamp generally involves molding (or physical cutting), grinding, drilling and other processes. Specifically, clamp units are typically first produced by molding and then mechanically bored using proper drilling equipment. Such method is not suitable for mass production and the positioning accuracy of the clamps fabricated is limited by the processing machine or mold used therein and generally could only reach tens to hundreds of microns. Therefore, the method usually employs additional equipment or a high precision processing machine for improving the positioning accuracy. This may cause high production costs and be the reason for sustained high prices of optical communications equipment and components. Moreover, in the practical use, due to the existence of manufacturing tolerances between different components, errors in sizes of holes in an individual optical fiber clamp and errors between locating holes of different optical fiber clamps, there are a low success rate of coupling at the first attempt, a high risk for the optical fibers and the optical fiber clamps to be damaged, and high operation and maintenance costs.